Modern microwave transmitter generally requires an accurate control of the radio frequency (RF) transmit power. In the wireless applications, automatic power level control, dynamic power control over various distances and accurate power level control to avoid excessive power to adjacent cells are a few examples of the importance of accurate power controls. At the microwave and millimeter wave bands, the power is also more expensive than the power at lower RF bands. These requirements suggest a need for an optimized design of a transition structure.